I. Field of the Invention
The present invention relates to an immunoassay.
II. Description of the Prior Art
Radioimmunoassay (RIA) for quantifying a specific antigen or antibody in a test sample is known as a conventional immunoassay. The RIA utilizes the antigen-antibody reaction of the antigen (or antibody) in the test sample collected from a patient with a corresponding antibody (or antigen) labeled with a radioisotope. An enzyme immunoassay for quantifying a specific antigen (or antibody) in a test sample is also well known. An antigen-antibody complex is produced by the antigen-antibody reaction between an antibody (or antigen) labeled with an enzyme and the corresponding antigen (or antibody) in the test sample collected from a patient. The antigen-antibody complex is quantified using the enzyme reaction of the marker enzyme.
These methods, however, can quantify only one kind of antigen (or antibody) at a time, and cannot quantify a plurality of kinds of antigens (or antibodies) simultaneously. Accordingly, for example, immunoassay procedures must be repeated three times where three different kinds of antigens (or antibodies) are to be quantified.
In order to diagnose infections diseases, chronic hepatic disorder, immune diseases or malignant tumors, each of the human immunoglobulins in blood, namely, IgG, IgA and IgM, are quantified. Similarly, the diagnosis of various cancers is made by quantifying various cancer markers in a test sample, such as .alpha.-fetoprotein, carcino embryonic antigen (CEA), C-reactive protein and ferrittin. Further, in order to diagnose cancers or various organic disorder, isozymes such as amylase and creatine kinase are seperately quantified recently. A strong demand accordingly exists for the provision of an immunoassay method capable of simultaneously quantifying more than one kind of antigen (or antibody).